High efficiency air conditioning system with humidity control

ABSTRACT

A heat recovery, dehumidifier and cooling system for ventilating fresh air to a conditioned space. The system is comprised of an enthalpy wheel or body for treating incoming fresh air to remove heat and moisture therefrom and means such as a duct for introducing fresh air to a first segment of the enthalpy wheel or body. A heat exchanger is provided in communication with the enthalpy wheel or body to receive pre-conditioned air having heat and moisture removed therefrom, the heat exchanger further lowering the temperature of the pre-conditioned air. A refrigerated surface is provided in a first communication with the heat exchanger to receive pre-conditioned air exiting from the sensible heat exchanger, the refrigerated surface further treating the pre-conditioned air to provide refrigerated air leaving the refrigerated surface having both lowered temperature and humidity. The refrigerated surface is provided in second communication with the heat exchanger to permit the refrigerated air leaving the refrigerator surface to be in heat exchange relationship with the pre-conditioned air from the enthalpy wheel or body as the pre-conditioned air passes through the sensible heat exchanger, the pre-conditioned air warming the refrigerated air as the conditioned air passes through the sensible heat exchanger to provide conditioned air.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/006,519, filed Nov. 9, 1995.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/006,519, filed Nov. 9, 1995.

BACKGROUND OF THE INVENTION

This invention relates to air conditioning and more particularly, itrelates to an improved air-conditioning system utilizing a heat recoveryand dehumidifier system.

ANSI/ASHRAE Standard 62-1989 has been established to address the needfor increased ventilation of buildings due to poor indoor air quality.Increased levels of contaminants from humans, fuel burning appliances,building materials and furnishings have resulted from the currentconstruction practices which produce tighter, low leakage buildings. Forexample, volatile organic compounds (VOCs) such as formaldehyde havebeen identified which with continued exposure can cause illness.Recommended ventilation rates proposed in this standard have beenincreased over previous standards and can range from about 15% at thelow end to 100% for buildings such as hospitals and laboratories. Theactual level of recommended outdoor air depends on the use, size andoccupancy of the building.

Indoor air quality is also affected by the presence of living organismsin the circulated air. Bacteria, mold and mildew, for example, thrive onthe damp air in air conditioning ducts. For this reason, recommendedrelative humidity levels are maintained at or below 60% where theseorganisms do not reproduce. In damp climates, bringing increased levelsof outdoor air into the building has made it difficult to maintaininterior humidity below 60%. Electric vapor compression systems removehumidity by water condensation across a cold coil. The dehumidificationprocess only occurs when the equipment is operating. When the systemcycles off and air enters the building, humidity increases. Manybuildings, especially newer ones, have a portion of their airconditioning system dedicated to treating 100% outdoor air. These unitscan operate continually and, therefore, perform a better job ofdehumidification. In very damp climates, this approach, however is stillnot sufficient to maintain the building relative humidity below 60%.Therefore, many systems have been designed to overcool the air and thenthe supply air is reheated to a comfortable temperature. This eliminatesthe cold clammy feel of the air but the systems are very inefficient inthat energy is expended for both cooling and reheating.

U.S. Pat. No. 5,179,998, assigned to Deschamps Laboratories, Inc.discloses a heat recovery ventilating dehumidifier which provides fresh,cool, low relative humidity air to a building or room during warmweather, and warm fresh air during cold weather. Fresh air is drawn intothe heat recovery ventilating dehumidifier, cooled and dehumidified byheat exchange by exhausting stale air in a first heat exchanger, thenfurther cooled and dehumidified by passage through a refrigerant coil.After passage through the refrigerant coil the fresh cool air passesthrough a second heat exchanger, cooling exhausting stale air and inexchange becoming less cool to reduce the relative humidity. The cool,fresh air having a lowered relative humidity is then used to ventilate abuilding or room. The cooled exhausting stale air then passes throughthe first heat exchanger cooling the fresh warm incoming air. However,there is always a need for improved efficiency in this type of system.

U.S. Pat. No. 5,372,182 discloses a modular recuperator apparatus andmethod that is used to pre-condition air treatment in a HVAC and airprocessing systems. A modular recuperating system enhances the overallefficiency of modem HVAC systems by reducing the required relativetreatment of air within the system by supplying pre-conditioned freshair into the system.

U.S. Pat. No. 3,977,466 discloses a room air conditioning apparatus forexchanging heat and/or moisture between fresh atmospheric air enteringthe room from the outside and consumed air being discharged from theroom. This apparatus combines high capacity with relatively smalldimensions, low air velocities and small pressure drops so as tominimize generation of disturbing noise. Within a casing, a motor-drivenregenerative-type rotor passes through two air stream zones in the firstof which is a motor-driven fan for discharge of consumed room air intothe outer atmosphere and in the second of which is a motor-driven fanfor supply of fresh air to the room from the outer atmosphere. In therotor, the two air streams exchange heat and/or moisture content so thatthe supply of fresh air is given a desired, predetermined temperatureand a desired moisture content.

U.S. Pat. No. 4,180,985 discloses an improved method and apparatus forair conditioning, using a refrigeration system. The disclosed method andapparatus provide for a refrigeration type air conditioning system to beequipped with a regeneratable desiccant for contacting moist feed airprior to passing the feed air across evaporator coils of the system. Thedesiccant removes a substantial portion of moisture from the feed air,thereby improving the efficiency of the air conditioning system. Thedesiccant material is regenerated by utilizing waste heat that isremoved from the condenser of the air conditioning system.

Thus, it will be seen that there is still a great need for an improvedsystem which provides substantially more cooling than provided by anevaporator. The present invention provides such an improved system.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an improvedair-conditioning system.

It is another object of this invention to provide an air-conditioningsystem utilizing heat recovery and dehumidification.

Yet, it is a further object of this invention to provide an improvedair-conditioning and ventilating system utilizing an enthalpy wheel, aheat exchanger and a refrigerated surface to provide fresh air havingboth lowered temperature and humidity.

These and other objects will become apparent from the specification anddrawings appended hereto.

In accordance with these objects, there is provided a heat recovery,dehumidifier and cooling system for ventilating fresh air to aconditioned space. The system is comprised of an enthalpy wheel or bodyfor treating incoming air to remove heat and moisture therefrom andmeans such as a duct for introducing incoming air to a first segment ofthe enthalpy wheel or body to provide pre-conditioned air. A sensibleheat exchanger is provided in communication with the enthalpy wheel orbody to receive pre-conditioned air having heat and moisture removedtherefrom, the heat exchanger further lowering the temperature of thepre-conditioned air. A refrigerated surface is provided in a firstcommunication with the heat exchanger to receive pre-conditioned airexiting from the heat exchanger, the refrigerated surface furthertreating the pre-conditioned air to provide refrigerated air leaving therefrigerated surface having both lowered temperature and humidity. Therefrigerated surface is provided in second communication with the heatexchanger to permit the refrigerated air leaving the refrigeratorsurface to be in heat exchange relationship with the pre-conditioned airfrom the enthalpy wheel or body as the pre-conditioned air passesthrough the heat exchanger, the pre-conditioned air warming therefrigerated air as the refrigerated air passes through the heatexchanger to provide conditioned air. Further, the heat exchanger isprovided in communication with the space to be conditioned to supply theconditioned air thereto. Means is provided for returning air from theconditioned space to the enthalpy wheel or body thereby providing areturn air, and means is provided for passing the return air through asegment of the enthalpy wheel or body to exchange sensible and latentheat from the return air to the enthalpy wheel or body thereby coolingthe enthalpy wheel or body. Means is provided for exhausting the returnair to the atmosphere after passing through the enthalpy wheel or body.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a flow chart showing steps of the invention incorporating theuse of an enthalpy wheel, a heat exchanger and refrigerated surface forconditioning air.

FIG. 2 shows a heat exchange wheel in a cassette.

FIG. 3 illustrates air flows, temperatures and moisture levels throughan enthalpy wheel and through a heat exchanger and evaporator coil.

FIG. 4 illustrates air flows, temperatures and moisture levels through aseat exchanger and evaporator coil.

FIG. 5 illustrates air flows, temperatures and moisture levels throughan evaporator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, there is shown a schematic flow chartillustrating steps in the invention. Generally, outdoor air or processair is introduced along line 2 to pump or blower 4. From pump or blower4, process air is introduced along line 6 to enthalpy or heat wheel 8where both heat and moisture are removed. After leaving enthalpy wheelor heat wheel 8, process air is passed along line 10 to sensible heatexchanger 12 where the temperature of the process air is reducedfurther. Condensation occurring in the heat exchanger can be removedusing a drip pan and drain. Process air from heat exchanger 12 isremoved along line 14 to evaporator coil 16 where the process air iscooled to a low temperature and also the humidity of the process air isreduced to provide chilled air having reduced humidity. The chilledprocess air from evaporator coil 16 is directed along line 18 to asecond side of heat exchanger 12 where the temperature of the chilledprocess air is heated before being introduced along line 19 toconditioned space 20. Return air is removed from conditioned space 20along line 22 using pump or blower 24. Return air from blower 24 isdirected along line 26 where it is introduced to enthalpy or heat wheel8 where it removes heat and moisture as it passes through heat orenthalpy wheel 8. After removing heat and moisture from wheel 8, thereturn air may be exhausted to the atmosphere or it may be introducedalong line 28 to contact condenser coil 30 for cooling refrigerantbefore being exhausted to the atmosphere. Additional outdoor air may beadded to line 28 if additional air is needed for condenser cooling.Alternatively, the condenser may be cooled by outside air.

Means may be provided for diverting a portion of the return air fromline 26 through line 27 into line 10 to provide a mix of return air andprocess air for introducing to heat exchanger 12. The amount of returnair diverted into line 10 can be controlled by baffle or valve 29.Diverting a portion of the return air has the advantage that it lowersthe load on the compressor and enthalpy wheel because it lowers theamount of outdoor air that has to be treated.

For purposes of providing refrigerant cooling, hot refrigerant isremoved from condenser coil 30 along line 42 to expansion valve 32 andthen into evaporator 16 where the refrigerant vaporizes and cools theprocess air to provide chilled air, e.g., 56° F. The vaporizedrefrigerant passes along line 46 to compressor 48 where it iscompressed. Then, the compressed refrigerant vapor passes along line 50to condenser coil 30 where it is liquefied.

A heat exchanger useful in the present invention can include anair-to-air heat exchanger, a heat pipe, or an air-to-liquid heatexchanger. In the use of a heat pipe, pre-conditioned air contacts aportion of the heat pipe prior to the pre-conditioned air contacting theevaporator. The pre-conditioned air is cooled and the fluid in the heatpipe is heated resulting in a phase change from liquid to vapor. Atanother portion of the heat pipe, the fluid is chilled by therefrigerated air condensing vapor to liquid. Thus, the refrigerated airis conditioned before entering the conditioned space. However, any heatexchanger can be used which transfers heat from the process air to thechilled or refrigerated air leaving evaporator 16. It will beappreciated that different arrangements may be used to transfer heatfrom the process to the chilled air, and such arrangements arecontemplated within the purview of the invention.

The present invention has the advantage that it can efficientlyintroduce fresh ventilation air having controlled humidity to a buildingor space to be conditioned, even in hot moist climates. This advantagecomes about, in part, by use of an enthalpy wheel in combination with aheat exchanger and an evaporation coil. This process is an effective wayto gain or improve compression cycle capacity and overall coefficient ofperformance (COP).

By lowering the temperature and humidity of the process air entering theheat exchanger by use of the enthalpy wheel, the temperature of processair entering the evaporator has a lowered temperature and humidity. Thisresults in higher cooling capacity of the evaporator. Air leaving theevaporator coil will be saturated at this colder temperature, giving adew point temperature essentially equivalent to the dry bulbtemperature.

Normally, an evaporator coil is not operated at a temperature coldenough to provide a conditioned space humidity which is too low. Coiltemperatures below 40° F. would be required to give less than 30%relative humidity at 72° F. in a conditioned space.

While the invention has been described with respect to the use of anenthalpy wheel, a heat exchanger and a refrigerant cooling coil orevaporator coil, it will be appreciated that any means which withdrawsheat from the process air and transfers heat to the process air leavingthe evaporator coil is contemplated within the purview of the invention.That is, the chilled air leaving the evaporator can be tempered byutilizing heat or removing heat from the process air to provideconditioned air for introducing to the conditioned space.

In the present invention, heat or enthalpy wheel 8 can be fabricatedfrom any material which is effective in removing heat and moisture fromincoming air on a continuous basis and which can be regenerated on acontinuous basis.

Referring now to FIG. 2, there is shown a schematic of an enthalpy wheel52 in accordance with the invention. The wheel, which is shown in acassette, has a central hub and shaft 54 for support means forsupporting the wheel within the cassette and a cylindrical outer casing56. Other support means may be used. Further, the wheel may have radialspokes extending from hub 54 to outer casting 56. Schematically, wheel52 is shown divided into two parts, 58 and 60. An exhaust air stream isshown exiting through part 58 and air or inlet stream is shown flowingthrough part 60 countercurrent to the exhaust stream. Wheel 52 transfersboth latent and sensible heat energy from the exhaust stream from a roomor building or the like to the intake stream to the room from a freshair supply stream. Depending on the season, in winter, for example,moisture in the exhaust stream is adsorbed by the wheel and desorbedinto the inlet stream. In summer, moisture in the make-up air isadsorbed by the wheel and removed from the wheel by the drier exhauststream. Also, in summer, the enthalpy wheel operates to cool the warnmake-up air. That is, the enthalpy wheel absorbs heat from the make-upair and transfers or exchanges the heat in the make-up air to theexhaust stream of air. These functions are performed on a continuousbasis as the wheel rotates and is regenerated by the countercurrentflow. The wheel typically rotates at a speed of about 1 to 50 rpm.

Between central hub 54 and outer casing 56 is a total heat energy andmoisture exchange or adsorbent media 62. In one embodiment, the media isfabricated by providing alternating layers of flat and corrugatedadsorbent paper or desiccant paper that is positioned to provide amultiplicity of open-ended passages parallel to the axis of rotation topermit air to flow therethrough. Typically, the media is formed bywinding a web of corrugated adsorbent paper or desiccant paper (having aflat sheet of paperboard bonded to one side) around hub 54 until amulti-layered media is built up that extends to outer casing 56. Thecorrugated adsorbent or desiccant paper having one side flat is made bybonding or positioning a flat strip of paperboard over a corrugatedstrip of desiccant paper. The width of the strip determines the width ofthe wheel and the edges of the paperboard forms the faces of the wheel.It should be understood that other fabrication techniques that formpassages, e.g., honeycomb-shaped passages and the like, may be used, allof which are contemplated within the purview of the invention.

While reference is made herein to paperboard, it should be understoodthat the corrugated strip of desiccant paper may be bonded to a flatstrip of metal such as copper or aluminum. Alternatively, metal coatedwith an adsorbent can be corrugated and wrapped or a metal corrugated orhoneycomb shape can be subsequently coated with adsorbent.

It should be understood that while the invention is described in wheelform, the invention can include a monolith of adsorbent or total heatenergy and moisture exchange media and an airstream for conditioning orregeneration may be directed alternately between different parts of themedia. Or, a fixed enthalpy exchanger which is comprised of a moisturepermeable membrane may be used. That is, a membrane which is permeableby moisture to transfer both latent and sensible heat may be used. Themoisture-permeable membrane can be free of desiccant. Further, while thedesiccant or adsorbent paper is described having the desiccant oradsorbent incorporated therein during fabrication of the paper, thepaper may be formed and desiccant or adsorbent coated thereon. Or, acombination of desiccant or adsorbent incorporation during paper makingand coating with desiccant or adsorbent thereafter may be used.

The improved desiccant paper in accordance with the invention iscomprised of desiccant or adsorbent, fibrous material and optionalbinders.

The desiccant can be any material capable of efficiently adsorbingmoisture from an air stream and capable of efficiently desorbing saidmoisture to a counter flowing air stream. Thus, the desiccant cancomprise the use of finely powdered solid, crystalline compounds capableof adsorbing and desorbing moisture from or to an air stream. Examplesof such adsorbants are silica gels, activated aluminas and molecularsieves or zeolites and the like and mixtures of these compounds. Othercompounds that may be used are halogenated compounds such as halogensalts including chloride, bromide and fluoride salts, for example.

The preferred desiccants are zeolites. The zeolites can be naturalcrystalline zeolites such as stilbite or synthetic crystallinealumino-silicates referred to as molecular sieves. These materials areactivated for adsorption by removing physically adsorbed water fromopenings in their molecular structure. Further, crystalline zeolites arepreferred desiccants over alumina and silica gel because they exhibitless hysteresis during desorption which provides a more efficientmoisture exchange between exit and intake air streams. In addition,zeolites are preferred desiccant material over activated aluminas andsilica gels because activated aluminas and silica gels have a wide poresize distribution, 8 Å to 70 Å for activated aluminas and 8 Å to 100 Åfor silica gels. The large pores in the structure can retain airbornecontaminants, some of which may impart odor, and these compounds can bedesorbed into the make-up air stream returning the contaminants andodors to the building. Thus, purification of air in the building hasbeen compromised. Thus, it is preferred to select an adsorbent thatrejects airborne contaminants. That is, the adsorbent should have a poresize large enough to adsorb moisture but small enough to rejectair-borne contaminants. In certain instances, the silica and alumina canbe combined with the zeolite, depending on the shape of the isothermdesired. For purposes of the invention, synthetic zeolites are preferredover natural zeolites because the natural-occurring zeolites can have abroader pore size distribution.

Synthetic zeolites include zeolites A, D, L, R, S, T, X and Y. Zeolite Ais a crystalline zeolite having the general formula:

    1±0.2M.sub.2-n O:Al.sub.2 O.sub.3 :1.85±0.5SiO.sub.2 :yH.sub.2 O

wherein M is metal, n is the valence of M and y may be any value up to6. The zeolitic molecular sieves generally known in the art as 4Amolecular sieves have a pore diameter of about 4 Å and have an aluminosilicate crystalline structure A with sodium cations. 3A sieves have analumino silicate structure A with sodium and potassium cations. In 3Amolecular sieves, most of the sodium cations in a 4A molecular sieve aresubstituted with potassium cations which results in most of the pores ina 3A molecular sieve being 3 Å in diameter. In 5A molecular sieves, mostof the sodium cations in a 4A molecular sieve are substituted withcalcium cation and most of the pores in the 5A molecular sieve haveabout a 5 Å diameter.

Zeolite X, for example, has an ideal composition given by:

    Na.sub.86  (AlO.sub.2).sub.86 ·(SiO.sub.2).sub.108 !·264H.sub.20

Cations may be exchanged so that the above formula is not absolute.Zeolites X and Y have topologically similar aluminosilicate frameworkstructures, although they are distinct zeolite species withcharacteristic differences. The chemical compositions of zeolites X andY are related to the synthesis method. The zeolites are distinguished onthe basis of chemical composition, structure and their related physicaland chemical properties. Differences are found in the cation compositionand distribution, the Si/Al ratio and possible Si--Al ordering intetrahedral sites. Typically, the Si/Al ratio for a zeolite X is between1 and 1.5 whereas it is greater than 1.5 for a Y zeolite. Zeolites HYand USY may be obtained from NaY zeolites by different schemes: thermaldecomposition of NH₄ ⁺, hydrogen ion exchange, hydrolysis of a zeolitecontaining multivalent cations during dehydration. By the use of"zeolite" or "molecular sieve" as used herein is meant to includealuminosilicates, aluminophosphates, silica aluminophosphates, silicatesand titanium aluminosilicates.

For purposes of the present invention, suitable molecular sieves include3A, 4A, 5A, 13X NaY, HY and USY with 3A and 4A molecular sieves beingpreferred.

Desiccant suitable for use in the present invention can have a particlesize ranging from 0.1 to 50 μm with a preferred particle size being 1 to4 μm.

In the present invention, any type of fibrous material can be used,including both fibrillated or non-fibrillated fibers. The fibers areformed by standard paper-making processes into adsorbent paper ordesiccant paper having adsorbent or desiccant contained therein.Examples of such fibers include wood pulp, e.g., cellulosic fibers, andsynthetic fibers and mixtures thereof. Inorganic fibers, such as glassor metal fibers and rock wool, etc., are not particularly suitable butmay be used in conjunction with fibrillated organic fibers. That is,non-fibrillated, inorganic and organic fibers may be used in conjunctionwith the fibrillated fibers. The amount of fibrillated andnon-fibrillated fibers can be adjusted to suit the particular need. Byfibrillated fiber as used herein is meant fiber shafts which are splitat their ends to form fibrils, i.e., fine fibers or filaments much finerthan the fiber shafts. Non-fibrillated fibers can includeresin-impregnated fibers.

Examples of fibrillated, synthetic organic fibers useful in theinvention include polymeric fibers selected from the group consisting ofhigh-density polyethylenes, high-density polypropylenes, aromaticpolyamides (aramids), polystyrenes, aliphatic polyamides, polyvinylchlorides, polyesters, nylons, rayons (cellulose acetate), acrylics,acrylonitrile homopolymers, copolymers with halogenated monomers,styrene copolymers, and mixtures of polymers (polypropylene withlow-density polyethylene, and high-density polyethylene withpolystyrene). Synthetic, organic fibers can be in staple form (choppedyarns), fabricated form (staple that has been refined) orextruded/precipitated form (i.e., polymer dissolved in a solventprecipitated by a nonsolvent or other forming technique).

The preferred fibers for forming into desiccant paper for use in thepresent invention are fibrillated aramid and acrylic fibers. Thepreferred aramid fiber is formed from a long-chain synthetic aromaticpolyamide having at least 85% of the amide (--CONH--) linkages directlyattached to the two aromatic rings. A preferred fibrillated aramid fiberis available from E. I. du Pont de Nemours & Company under thedesignation KEVLAR® 303. In forming fibrillated KEVLAR® material, highshear is applied to KEVLAR® fiber shafts which split at their ends intofibrils to create a tree-like structure. In the production of adsorbentor desiccant paper, the fibrils interlock to enhance the paper strengthand provide increased area for capturing or securing adsorbentparticles. Additional refining of the fibers may be performed to furtherenhance paper strength. KEVLAR® is stable in oxidizing atmospheres up to450° C. Other high-temperature aramid fibers such as NOMEX® availablefrom Du Pont, TWARON® available from AKZO Fibers Inc., and TEIJINCONEX®and TECHNORA® available from Teijin Ltd. Japan, are also suitablematerials.

Other preferred fiber which have been found to be highly suitable in thepresent invention are acrylic fibers such as fibrillated acrylic fibersavailable from American Cyanamid under the designation CFF®.

It should be noted that if the fibers are not available in fibrillatedform, fibers can be fibrillated by transferring a slurry of the fibersto a disc or other high shear refiner to split the ends of the choppedfibers or shafts to provide fibrils thereon. In addition, fibrillatedshafts available from the manufacturer can be further refined toincrease the degree of fibrillation on the shafts which results in ahigher degree of interlocking and consequently stronger desiccant oradsorbent paper.

Thus, preferably the shafts or chopped fibers can be provided in alength in the range of 1 to 30 mm, and typically in the range of 3 to 15mm, prior to fibrillation. Further, preferably the shafts or choppedfibers have a diameter in the range of 1 to 50, typically 5 to 25 μm,prior to fibrillation. In fibrillated form, such chopped fibers havefibrils extending therefrom having lengths in the range of 0.5 to 28 mmand preferably in the range of 1 to 10 mm, and such fibrils typicallyhave a diameter in the range of 0.5 to 40 μm and preferably in the rangeof 1 to 10 μm.

The fibrillation of the chopped fibers is an important aspect of thepresent invention. That is, it has been discovered that not only do thefibrillated fibers provide for higher strength in the desiccant oradsorbent paper, but also, it provides for thinner desiccant paper whichis very important because of the resultant reduced air flow pressuredrop across the media during operation. Further, more efficientadsorption and desorption is achieved. That is, an enthalpy wheel can bemade deeper or wider for better adsorption and yet not require higherpressures, thereby raising the efficiency of the wheel. For example,enthalpy wheels formed from the improved desiccant paper can have up toabout 25% increase in depth for about the same pressure drop across thewheel.

The fibrillated fibers are important in yet another way. That is,surprisingly, it has been discovered that higher loading of desiccant oradsorbent can be achieved utilizing fibrillated fibers. That is, thefibrils not only provide for thinner and stronger adsorbent paper, butthe fibrils provide additional surface area on and in which desiccant oradsorbent can attach or anchor. Thus, compared to non-fibrillatedshafts, fibrillated fibers provide for higher loading of desiccant oradsorbent in paper having desiccant or adsorbent dispersed thereinwithout loss in strength of the paper.

The paper of the present invention can be prepared by wet-laying thedesiccant and fibrillated fibers into a continuous sheet or web or intoa hand sheet. The paper may then be formed into a single-facedcorrugated laminate, which is spirally wrapped to make the adsorbentwheel. The fibrillated organic fibers provide highly suitablereinforcement at levels as low as 15 wt. % of the total desiccant paperstructure due to their strength and ability to interlock. Some desiccantpapers of suitable strength can be made having less than 10 wt. % fiberswith very high sorbent loading when made in accordance with theinvention.

Desiccant or adsorbent paper used in wheels in accordance with theinvention can comprise 5 to 85 wt. % desiccant or adsorbent, theremainder comprising fibrous material. Binder can be added as needed.For example, if cellulose fibers from wood pulp are used in sufficientquantity, binder does not have to be added. Typical composition rangescan comprise 5 to 70 wt. % desiccant or adsorbent, the remaindercomprising fibrous material and binder. A typical composition comprisesabout 38 wt. % fibrous material, about 50 wt. % desiccant or adsorbentand about 12 wt. % binder. The adsorbent paper can contain 15 to 75 wt.%, typically 30 to 55 wt. %, fibrillated fibers, 1 to 20 wt. %,typically 5 to 15 wt. %, binder with the balance being adsorbent.

The desiccant or adsorbent paper thus formed containing solid desiccantor adsorbent dispersed therein during the paper manufacturing processesare formed into heat and moisture transfer bodies such as total energytransfer wheels or enthalpy wheels. Additionally, the adsorbent papercan be formed into mass transfer bodies such as adsorbent fillers forcontaminants. For example, the desiccant or adsorbent paper can beformed into such wheels by the formation of corrugated paper having thedesired thickness and periodicity and bonded to a flat paperboard ofsimilar composition to produce a single-faced corrugated sheet. Thesingle-faced corrugated sheet is spirally rolled into a wheelconfiguration with the passages or channels formed by the corrugationsand flat paperboard being parallel to the axial direction of the wheel.To maximize heat and mass transfer, the paperboard should be as thin aspossible while maintaining strength to minimize the pressure drop acrossthe wheel. Thin paperboard permits the manufacture of smaller channelsto provide higher surface area for heat and mass transfer.

In this manner, an enthalpy wheel can be manufactured that provides forimproved levels of moisture and heat transfer. Further, the enthalpywheel can be readily mass produced in a cost effective manner.Conventional paper-making equipment and corrugating equipment can beused for manufacturing.

The advantages of the present invention are illustrated by modeling aheat recovery and dehumidification system in accordance with theinvention as set forth in FIG. 3. For purposes of the system,illustrated in FIG. 3, outdoor air at 95° F., 0.01843 lbs H₂ O/lb of airand a dew point of 74.5° F. is introduced to an enthalpy wheel at 2000SCFM. The air removed from the enthalpy wheel is reduced to atemperature of 78.1° F. and contained 0.01295 lbs H₂ O/lb of air. Theair from the enthalpy wheel is introduced to a first side of anair-to-air heat exchanger where the temperature is reduced to 65.1° F.The air from the air-to-air heat exchanger is introduced to anevaporative coil where the temperature is reduced to 56.3° F. and thehumidity is reduced to 0.00986 lbs H₂ O/lb of air. The air from theevaporative coil is introduced to the second side of an air-to-air heatexchanger to cool the air from the enthalpy wheel passing through thefirst side of the air-to-air heat exchanger. Thus, the air from theevaporative coil is heated in the air-to-air heat exchanger to atemperature of 69.4° F. while maintaining the same level of humidity.Thus, air is supplied to the conditioned space at 69.4° F. and ahumidity level of 0.00966 lbs H₂ O/lb of air. For purposes of coolingand removing moisture, return air from the conditioned space isintroduced to the enthalpy wheel at about 75° F. and a humidity level of0.01100 lbs H₂ O/lb of air. Air is exhausted from the enthalpy wheel atabout 92° F. and a humidity level of 0.01648 lbs H₂ O/lb of air. Thestate points are provided in Table 1. About 5.3 tons of cooling resultfrom the use of the enthalpy wheel providing a total of 12 tons ofcooling when treating 2000 SCFM of outdoor air. As noted, theconditioned air can be supplied to a conditioned space at 69.4° F., at ahumidity level of 0.00966 lbs H₂ O/lb of air which is well belowbuilding neutral conditions for both temperature and moisture contentaiding in maintaining a low humidity in the conditioned space. Theenergy efficiency ratio (EER) which is the ratio of cooling capacity(BTU/h) to electricity used (watts) of the modeled unit including powerrequired for blowers is 19.7 BTU/h/W.

                                      TABLE 1                                     __________________________________________________________________________               Dew                                                                       Temp.                                                                             Pt.                                                                              Rate                                                                             Rate                                                                             Flow                                                                              W   W   RH Enthalpy                                          °F.                                                                        °F.                                                                       cfm                                                                              scfm                                                                             lb/min                                                                            lb/lb                                                                             gr/lb                                                                             %  BTU/lb                                     __________________________________________________________________________    1 Outdoor                                                                            95.0                                                                              74.5                                                                             2170                                                                             2000                                                                             150.7                                                                             0.01843                                                                           129.0                                                                             51.8                                                                             43.13                                      2 E Wheel                                                                            78.1                                                                              674.5                                                                            2086                                                                             2000                                                                             150.7                                                                             0.01295                                                                           96.6                                                                              62.8                                                                             32.94                                        Out                                                                         3 Heat 65.1                                                                              64.5                                                                             2035                                                                             2000                                                                             150.7                                                                             0.01295                                                                           96.6                                                                              97.8                                                                             29.73                                        Exchanger                                                                     Out                                                                         4 Coil Out                                                                           56.3                                                                              56.3                                                                             1991                                                                             2000                                                                             150.7                                                                             0.00966                                                                           67.6                                                                              100.0                                                                            24.02                                      5 Supply                                                                             69.4                                                                              56.4                                                                             2042                                                                             2000                                                                             150.7                                                                             0.00966                                                                           67.6                                                                              63.1                                                                             27.21                                      6 Return                                                                             75.0                                                                              59.9                                                                             2068                                                                             2000                                                                             150.7                                                                             0.01100                                                                           77.00                                                                             59.4                                                                             30.04                                      7 Exhaust                                                                            92.0                                                                              71.3                                                                             2152                                                                             2000                                                                             150.7                                                                             0.01648                                                                           115.4                                                                             51.1                                                                             40.24                                      __________________________________________________________________________

In the example modeled in FIG. 4, an enthalpy wheel is not used to moveheat or moisture from the outdoor air. Further, air flow is maintainedat 2000 SCFM. Thus, air is introduced to the first side of an air-to-airheat exchanger at a rate of 2000 SCFM, at 95° F. containing 0.01843 lbsH₂ O/lb of air. The temperature is lowered to 82.1° F. and the humidityis still 0.01843 lbs H₂ O/lb of air. After the evaporator coil, thetemperature of the air is lowered to 56.4° F. and the humidity loweredto 0.00968 lbs H₂ O/lb of air.

The air from the evaporator coil is introduced to the second side of theair-to-air heat exchanger where it is heated to 69.3° F. Thus, thesupply air to the conditioned space had a temperature of 69.3° F. and ahumidity level of 0.00968 lbs H₂ O/lb of air. However, the disadvantageof this system is that the EER is 8.8 and the cost of operating systemis over twice that for the system in FIG. 1. The state points are setforth in Table 2. The EER was only 8.8 BTU/h/W including power forblowers.

                                      TABLE 2                                     __________________________________________________________________________               Dew                                                                       Temp.                                                                             Pt.                                                                              Rate                                                                             Rate                                                                             Flow                                                                              W   W   RH Enthalpy                                          °F.                                                                        °F.                                                                       cfm                                                                              scfm                                                                             lb/min                                                                            lb/lb                                                                             gr/lb                                                                             %  BTU/lb                                     __________________________________________________________________________    1 Outdoor                                                                            95.0                                                                              74.5                                                                             2170                                                                             2000                                                                             150.7                                                                             0.01843                                                                           129.0                                                                             51.8                                                                             43.13                                      2 E Wheel                                                                            95.0                                                                              74.5                                                                             2170                                                                             2000                                                                             150.7                                                                             0.01843                                                                           129.0                                                                             51.8                                                                             43.13                                        Out                                                                         3 Heat 82.1                                                                              74.5                                                                             2119                                                                             2000                                                                             150.7                                                                             0.01843                                                                           129.0                                                                             77.9                                                                             39.92                                        Exchanger                                                                     Out                                                                         4 Coil Out                                                                           56.4                                                                              56.4                                                                             1991                                                                             2000                                                                             150.7                                                                             0.00968                                                                           67.8                                                                              100.0                                                                            24.05                                      5 Supply                                                                             69.3                                                                              56.5                                                                             2041                                                                             2000                                                                             150.7                                                                             0.00968                                                                           67.8                                                                              63.4                                                                             27.21                                      6 Return                                                                             75.0                                                                              59.9                                                                             2066                                                                             2000                                                                             150.7                                                                             0.01100                                                                           77.0                                                                              59.4                                                                             30.04                                      7 Exhaust                                                                            75.0                                                                              60.0                                                                             2066                                                                             2000                                                                             150.7                                                                             0.01100                                                                           77.0                                                                              59.4                                                                             30.04                                      __________________________________________________________________________

For purposes of comparison, inlet air is introduced to an evaporatorcoil at 2000 SCFM, 95° F. and 0.01843 lbs H₂ O/lb of air. No enthalpywheel or air-to-air heat exchanger is used in this model. The air iscooled to 61.2° F. at 0.01151 lbs H₂ O/lb of air, as shown in FIG. 5.The state points for this system are provided in Table 3. In this case,the supply or conditioned air is colder but the moisture level is abovebuilding neutral which is maximum 0.011 lbs H₂ O/lb of air. This permitsmoisture to build up in the conditioned space unless theair-conditioning system is large enough to remove it. Thus, the highmoisture places an additional load on the air-conditioning system. Thissystem is also inefficient with operating costs being about the same asthe system in FIG. 4. Thus, it will be seen that the systems of FIGS. 4and 5 are much less efficient than that of the invention.

                                      TABLE 3                                     __________________________________________________________________________               Dew                                                                       Temp.                                                                             Pt.                                                                              Rate                                                                             Rate                                                                             Flow                                                                              W   W   RH Enthalpy                                          °F.                                                                        °F.                                                                       cfm                                                                              scfm                                                                             lb/min                                                                            lb/lb                                                                             gr/lb                                                                             %  BTU/lb                                     __________________________________________________________________________    1 Outdoor                                                                            95.0                                                                              74.5                                                                             2170                                                                             2000                                                                             150.7                                                                             0.01843                                                                           129.0                                                                             51.8                                                                             43.13                                      2 E Wheel                                                                            95.0                                                                              74.5                                                                             2170                                                                             2000                                                                             150.7                                                                             0.01843                                                                           129.0                                                                             51.8                                                                             43.13                                        Out                                                                         3 Heat 95.0                                                                              74.5                                                                             2170                                                                             2000                                                                             150.7                                                                             0.01843                                                                           129.0                                                                             51.8                                                                             43.13                                        Exchanger                                                                     Out                                                                         4 Coil Out                                                                           61.2                                                                              61.2                                                                             2016                                                                             2000                                                                             150.7                                                                             0.01151                                                                           80.6                                                                              100.0                                                                            27.21                                      5 Supply                                                                             61.2                                                                              61.2                                                                             2016                                                                             2000                                                                             150.7                                                                             0.01151                                                                           80.6                                                                              100.0                                                                            27.21                                      6 Return                                                                             75.0                                                                              59.9                                                                             2068                                                                             2000                                                                             150.7                                                                             0.01100                                                                           77.0                                                                              59.4                                                                             30.04                                      7 Exhaust                                                                            75.0                                                                              60.0                                                                             2068                                                                             2000                                                                             150.7                                                                             0.01100                                                                           77.0                                                                              59.4                                                                             30.04                                      __________________________________________________________________________

While the invention has been described in terms of preferredembodiments, the claims appended hereto are intended to encompass otherembodiments which fall within the spirit of the invention.

What is claimed is:
 1. A heat recovery, dehumidifier and cooling systemfor ventilating fresh air to a conditioned space, the system comprisedof:(a) an enthalpy wheel or body for treating incoming outdoor air toremove heat and moisture therefrom; (b) a means for introducing outdoorair to a first segment of said enthalpy wheel or body to providepre-conditioned air; (c) a heat exchanger in communication with saidenthalpy wheel or body to receive pre-conditioned air having heat andmoisture removed therefrom, said heat exchanger further lowering thetemperature of said pre-conditioned air; (d) a refrigerated surface in afirst communication with said heat exchanger to receive pre-conditionedair exiting from said heat exchanger, said refrigerated surface furthertreating said pre-conditioned air to provide refrigerated air leavingsaid refrigerated surface having both lowered temperature andhumidity,(i) said refrigerated surface in a second communication withsaid heat exchanger to permit said refrigerated air leaving saidrefrigerator surface to be in heat exchange relationship with saidpre-conditioned air from said enthalpy wheel or body as saidpre-conditioned air passes through said heat exchanger, saidpre-conditioned air warming said refrigerated air as said refrigeratedair passes through said heat exchanger to provide conditioned air, (ii)said heat exchanger in communication with said space to be conditionedto supply said conditioned air thereto; (e) means for returning air fromsaid conditioned space to said enthalpy wheel or body thereby providinga return air; (f) means for passing said return air through a segment ofsaid enthalpy wheel or body to exchange sensible and latent heat fromsaid return air to said enthalpy wheel or body thereby cooling saidenthalpy wheel or body; and (g) means for exhausting said return air tothe atmosphere after passing through said enthalpy wheel or body.
 2. Theheat recovery, dehumidifier and cooling system in accordance with claim1 wherein said enthalpy wheel or body is comprised of gas permeablemedia having a multiplicity of passageways therethrough through which anair stream can flow, the media comprised of fibrous support material anda desiccant material, said media capable of adsorbing heat and moisturefrom a warm, moist air stream flowing through said passageways andreleasing heat and moisture to a cooler, drier stream flowing throughsaid passageways.
 3. The heat recovery, dehumidifier and cooling systemin accordance with claim 2 wherein said media is comprised of 5 to 90wt. % desiccant material.
 4. The heat recovery, dehumidifier and coolingsystem in accordance with claim 2 wherein said fibrous material isselected from the group consisting of cellulosic fibers and syntheticorganic fibers.
 5. The heat recovery, dehumidifier and cooling system inaccordance with claim 2 wherein the fibrous material is an organicsynthetic fibrous material selected from the group consisting ofpolyethylene, polypropylene, acrylic, acetate, nylon and polyaramidfibers.
 6. The heat recovery, dehumidifier and cooling system inaccordance with claim 2 wherein said desiccant is selected from at leastone of the group consisting of activated alumina, silica gels andcrystalline zeolites.
 7. The heat recovery, dehumidifier and coolingsystem in accordance with claim 2 wherein said desiccant is crystallinezeolites.
 8. The heat recovery, dehumidifier and cooling system inaccordance with claim 2 wherein said desiccant is a zeolite selectedfrom one of the group consisting of 3A, 4A, 5A, 13X NaY, HY and USY. 9.The heat recovery, dehumidifier and cooling system in accordance withclaim 2 wherein said desiccant is a zeolite selected from one of thegroup consisting of 3A and 4A zeolites.
 10. The heat recovery,dehumidifier and cooling system in accordance with claim 2 wherein saiddesiccant is a 3A zeolite.
 11. The heat recovery, dehumidifier andcooling system in accordance with claim 2 wherein said desiccant is a 4Azeolite.
 12. The heat recovery, dehumidifier and cooling system inaccordance with claim 1 including means for diverting a portion of thereturn air to said heat exchanger with said pre-conditioned air.
 13. Theheat recovery, dehumidifier and cooling system in accordance with claim1 wherein said heat exchanger is a sensible heat exchanger.
 14. The heatrecovery, dehumidifier and cooling system in accordance with claim 1wherein said heat exchanger is a heat pipe.
 15. The heat recovery,dehumidifier and cooling system in accordance with claim 1 wherein saidheat exchanger is an air-to-air heat exchanger.
 16. The heat recovery,dehumidifier and cooling system in accordance with claim 1 wherein saidheat exchanger is an air-to-liquid heat exchanger.
 17. A heat recovery,dehumidifier and cooling system for ventilating fresh air to aconditioned space, the system having a condenser coil, an evaporatorcoil and a compressor, the system comprised of:(a) an enthalpy wheel orbody for treating air to remove heat and moisture therefrom; (b) a ductfor introducing air to a first segment of said enthalpy wheel or body toprovide pre-conditioned air; (c) a heat exchanger in communication withsaid enthalpy wheel or body to receive pre-conditioned air having heatand moisture removed therefrom, said heat exchanger further lowering thetemperature of said pre-conditioned air; (d) an evaporator coil in afirst communication with said heat exchanger to receive pre-conditionedair exiting from said heat exchanger, said evaporator coil furthertreating said pre-conditioned air to provide refrigerated air leavingsaid evaporator coil having both lowered temperature and humidity,(i)said evaporator coil in a second communication with said heat exchangerto permit said refrigerated air leaving said evaporator coil to be inheat exchange relationship with said pre-conditioned air from saidenthalpy wheel or body as said pre-conditioned air passes through saidheat exchanger, said pre-conditioned air warming said refrigerated airas said refrigerated air passes through said heat exchanger to provideconditioned air, (ii) said heat exchanger in communication with saidspace to be conditioned to supply said conditioned air thereto; (e)liquid refrigerant from a condenser coil adapted to pass through saidevaporator coil; (f) an expansion valve or orifice in fluidcommunication between said condenser coil and said evaporator coil forvaporizing said liquid refrigerant from said condenser coil into saidevaporating coil thereby imparting cooling to said pre-conditioned airpassing through said evaporator coil; (g) a compressor in communicationwith said evaporator coil and said condenser coil for compressingvaporized refrigerant for recirculating back to said condenser coil; (h)means for returning air from said conditioned space to said enthalpywheel or body thereby providing a return air; (i) means for passing saidreturn air through a segment of said enthalpy wheel or body to exchangesensible and latent heat from said return air to said enthalpy wheel orbody thereby cooling said enthalpy wheel or body; and means forexhausting said return air to the atmosphere after passing through saidenthalpy wheel or body.
 18. A heat recovery, dehumidifier and coolingsystem for ventilating fresh air to a conditioned space, the systemhaving a condenser coil, an evaporator coil and a compressor, the systemcomprised of:(a) an enthalpy wheel or body for treating incoming freshair to remove heat and moisture therefrom, said enthalpy wheel or bodycomprised of a gas permeable media having a multiplicity of passagewaysthrough which a fresh air stream can flow, the media comprised of afibrous support material and a zeolite desiccant selected from the groupconsisting of 3A, 4A, 5A, 113X, NaY, HY and USY, said media capable ofadsorbing heat and moisture from a warm, humid stream of fresh air andreleasing heat and moisture to a cooler, drier stream; (b) means forintroducing fresh air to a first segment of said enthalpy wheel or bodyto provide pre-conditioned air; (c) a heat exchanger in communicationwith said enthalpy wheel or body to receive pre-conditioned air havingheat and moisture removed therefrom, said heat exchanger furtherlowering the temperature of said pre-conditioned air; (d) an evaporatorcoil in a first communication with said heat exchanger to receivepre-conditioned air exiting from said heat exchanger, said evaporatorcoil further treating said pre-conditioned air to provide refrigeratedair leaving said evaporator coil having both lowered temperature andhumidity,(i) said evaporator coil in a second communication with saidheat exchanger to permit said refrigerated air leaving said evaporatorcoil to be in heat exchange relationship with said pre-conditioned airfrom said enthalpy wheel or body as said pre-conditioned air passesthrough said heat exchanger, said pre-conditioned air warming saidrefrigerated air as said refrigerated air passes through said heatexchanger to provide conditioned air, (ii) said heat exchanger incommunication with said space to be conditioned to supply saidconditioned air thereto; (e) liquid refrigerant from a condenser coiladapted to pass through said evaporator coil; (f) an expansion valve ororifice in fluid communication between said condenser coil and saidevaporator coil for vaporizing said liquid refrigerant from saidcondenser coil into said evaporating coil thereby imparting cooling tosaid pre-conditioned air passing through said evaporator coil; (g) acompressor in communication with said evaporator coil and said condensercoil for compressing vaporized refrigerant for recirculating back tosaid condenser coil; (h) means for returning air from said conditionedspace to said enthalpy wheel or body thereby providing a return air; (i)means for passing said return air through a segment of said enthalpywheel or body to exchange sensible and latent heat from said return airto said enthalpy wheel or body thereby cooling said enthalpy wheel orbody; (j) means for exhausting said return air to the atmosphere afterpassing through said enthalpy wheel or body.
 19. A method ofconditioning air to be introduced to a conditioned space by removingheat and moisture therefrom, the method comprising the steps of:(a)providing an enthalpy wheel or body for treating air to remove heat andmoisture therefrom; (b) introducing air to a first segment of saidenthalpy wheel or body to remove heat and moisture therefrom to providepre-conditioned air; (c) providing a heat exchanger in communicationwith said enthalpy wheel or body; (d) passing said pre-conditioned airthrough a first side of said heat exchanger to remove heat therefrom;(e) providing an evaporator coil in communication with said heatexchanger; (f) introducing said pre-conditioned air from said heatexchanger to said evaporator coil to further lower the temperature andhumidity to provide refrigerated air; (g) directing refrigerated airthrough a second side of said heat exchanger thereby raising thetemperature of said refrigerated air as said refrigerated air passesthrough said heat exchanger to provide conditioned air for introducingto a conditioned space; and (h) supplying refrigerant to said evaporatorcoil for cooling said pre-conditioned air by vaporizing said refrigerantin said evaporator coil and thereafter recirculating said vaporizedrefrigerant through a compressor to provide compressed refrigerant vaporand then recirculating the compressed refrigerant vapor through acondenser coil for condensing said compressed refrigerant vapor prior toits returning to said evaporator coil.
 20. The method in accordance withclaim 19 wherein said enthalpy wheel or body is comprised of gaspermeable media having a multiplicity of passageways therethroughthrough which an air stream can flow, the media comprised of fibroussupport material and a desiccant material, said media capable ofadsorbing heat and moisture from a warm, moist air stream flowingthrough said passageways and releasing heat and moisture to a cooler,drier stream flowing through said passageways.
 21. The method inaccordance with claim 20 wherein said media is comprised of 5 to 90 wt.% desiccant material.
 22. The method in accordance with claim 20 whereinsaid fibrous material is selected from the group consisting ofcellulosic fibers and synthetic organic fibers.
 23. The method inaccordance with claim 20 wherein the fibrous material is an organicsynthetic fibrous material selected from the group consisting ofpolyethylene, polypropylene, acrylic, acetate, nylon and polyaramidfibers.
 24. The method in accordance with claim 20 wherein saiddesiccant is selected from at least one of the group consisting ofactivated alumina, silica gels and crystalline zeolites.
 25. The methodin accordance with claim 20 wherein said desiccant is crystallinezeolites.
 26. The method in accordance with claim 20 wherein saiddesiccant is a zeolite selected from one of the group consisting of 3A,4A, 5A, 13X, NaY, HY and USY.
 27. The method in accordance with claim 20wherein said desiccant is a zeolite selected from one of the groupconsisting of 3A and 4A zeolites.
 28. The method in accordance withclaim 20 wherein said desiccant is a 3A zeolite.
 29. The method inaccordance with claim 20 wherein said desiccant is a 4A zeolite.
 30. Themethod in accordance with claim 20 including the step of regeneratingsaid enthalpy wheel or body by contacting said wheel or body with airexhausted from said conditioned space.
 31. The method in accordance withclaim 30 including the step of cooling said condenser coil with air usedto regenerate said enthalpy wheel or body.
 32. The method in accordancewith claim 20 including the step of cooling said condenser coil withoutside air.
 33. The method in accordance with claim 19 including thestep of providing a return air from said conditioned space and directingsaid return air through said enthalpy wheel or body thereby cooling saidenthalpy wheel or body.
 34. The method in accordance with claim 33including diverting a portion of said return air to said pre-conditionedair for passing through said heat exchanger.
 35. The method inaccordance with claim 19 wherein said heat exchanger is a sensible heatexchanger.
 36. The method in accordance with claim 19 wherein said heatexchanger is an air-to-air heat exchanger.
 37. The method in accordancewith claim 19 wherein said heat exchanger is a heat pipe.
 38. The methodin accordance with claim 19 wherein said heat exchanger is anair-to-liquid heat exchanger.
 39. A method of conditioning air to beintroduced to a conditioned space by removing heat and moisturetherefrom, the method comprising the steps of:(a) providing an enthalpywheel or body for treating air to remove heat and moisture therefrom;(b) introducing air to a first segment of said enthalpy wheel or body toremove heat and moisture therefrom to provide pre-conditioned air; (c)providing a heat exchanger in communication with said enthalpy wheel orbody; (d) passing said pre-conditioned air through a first side of saidheat exchanger to remove heat therefrom; (e) providing an evaporatorcoil in communication with said heat exchanger; (f) introducing saidpre-conditioned air from said heat exchanger to said evaporator coil tofurther lower the temperature and humidity to provide refrigerated air;(g) directing refrigerated air through a second side of said heatexchanger thereby raising the temperature of said refrigerated air assaid refrigerated air passes through said heat exchanger to provideconditioned air for introducing to a conditioned space; (h) supplyingrefrigerant to said evaporator coil for cooling said pre-conditioned airby vaporizing said refrigerant in said evaporator coil and thereafterrecirculating said vaporized refrigerant through a compressor to providecompressed refrigerant vapor and then recirculating the compressedrefrigerant vapor through a condenser coil for condensing saidcompressed refrigerant vapor prior to its returning to said evaporatorcoil (i) returning air from said conditioned space to said enthalpywheel or body thereby providing a return air; and (j) passing saidreturn air through a segment of said enthalpy wheel or body to exchangesensible and latent heat from said return air to said enthalpy wheel orbody thereby cooling said enthalpy wheel or body.
 40. The method inaccordance with claim 39 including diverting a portion of said returnair to said pre-conditioned air for passing through said heat exchanger.41. The method in accordance with claim 39 wherein said heat exchangeris a sensible heat exchanger.
 42. The method in accordance with claim 39wherein said heat exchanger is an air-to-air heat exchanger.
 43. Themethod in accordance with claim 39 wherein said heat exchanger is a heatpipe.
 44. The method in accordance with claim 39 wherein said heatexchanger is an air-to-liquid heat exchanger.